Flavans

PhytochemicalFlavonoid

What is it

Flavans are a class of polyphenolic compounds and the structural backbone of catechins, proanthocyanidins, and many tea, cocoa, and grape polyphenols. 'Dimer flavans' refers to proanthocyanidin B-type dimers.

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Vascular function (as cocoa flavanols)

Strong Evidence

Multiple randomized trials including the COSMOS trial of cocoa flavanols show modest improvements in endothelial function and cardiovascular event reduction with regular intake.

Blood pressure

Good Evidence

Meta-analyses of cocoa flavanols show small but consistent reductions in blood pressure (about 2-3 mmHg systolic).

How it works

Flavans and their oligomers (proanthocyanidins) act as antioxidants and modulate vascular endothelial function, partly by influencing nitric oxide signaling and platelet activity. They are studied extensively in cocoa, green tea, and grape seed contexts for cardiovascular benefits.

Dosage

No standardized dose for isolated flavans. Cocoa or grape seed extracts standardized to flavanols are typically dosed at 200-900 mg/day.

When and how to take it

Take separately from iron supplements (2-hour gap) to avoid reduced iron absorption. Food intake does not strongly affect flavan absorption.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Cocoa flavanol extract

Most studied form; standardized to flavanol content.

Catechin and proanthocyanidin absorption is moderate; metabolites circulate

Grape seed extract (proanthocyanidins)

Common alternative source of dimer and oligomer flavans.

Polymerization affects absorption

Safety

Generally well tolerated at typical supplement doses. High intakes can cause stomach upset and may inhibit non-heme iron absorption.

Who should be cautious

Use caution in pregnancy with concentrated extracts (food levels are fine). People on anticoagulant therapy should be cautious with high-dose products.

Interactions

May modestly inhibit platelet aggregation; discuss with a clinician before surgery or alongside anticoagulants. May interact with iron supplements if taken simultaneously.

Food sources

Cocoa and dark chocolate

Amount
rich in flavanols
%DV
—

Green tea

Amount
rich in catechins
%DV
—

Grape seeds and skins

Amount
rich in proanthocyanidins
%DV
—

Frequently asked questions

What is the difference between flavans and flavonoids?⌄

Flavans are a sub-class of flavonoids with a specific saturated structure. They include catechins and proanthocyanidins.

Should I take flavan supplements?⌄

Food sources (cocoa, tea, berries) provide flavans alongside other beneficial compounds. Supplements can supply higher concentrations but consider drug interactions.

References

Flavans on Wikidata — Wikidata link

Flavans on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Flavans (PubMed search) — PubMed link

Track Flavans with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.